Chapter 15 Staying Physically Active: A Way of Life
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Reaction Time
Reaction time is the amount of
time it takes you to respond to a signal
once you receive the signal. In most
physical activities, your response will
be some type of movement. A soccer
goalie needs good reaction time to
block a ball headed for the net. A driver
needs to be able to react to changes
in traffi c. Playing baseball, basket-
ball, football, or softball can help you
strengthen your reaction time, 15-10.
How Fit Are You?
You can assess yourself in each
health and skill component of physical
fi tness through a variety of simple tests.
For example, the President’s Challenge
on Physical Fitness can be found on the
Internet and offers instruction on how
to test your ability in several areas of
fi tness. You are likely to fi nd you are
strong in some components but weak
in others. To be totally fi t, you should
be moderately strong in all the health
components. You can set goals to
improve in your weaker areas. Building
strength in each of the health areas will
also help you develop more of the skill
components.
Later in the chapter you will
read about how to plan an exercise
program and stay motivated to follow it.
Following the guidelines outlined will
help you plot a strategy for improving
your total fi tness.
Exercise and
Heart Health
Physical inactivity is a risk factor
for coronary heart disease (CHD). As
higher levels of physical fi tness are
achieved, the risks of death from heart
disease decline.
Exercise affects the cardiovascular
system (the heart and blood vessels)
in several complex ways to improve
overall heart health. Remember that
exercise helps develop cardiorespira-
tory fi tness. One indication of this type
of fi tness is a slower heartbeat. The
heart beats slower because it is able to
work more effi ciently. It pumps more
blood with each beat. This improved
effi ciency puts less strain on the heart
muscle.
Another way exercise affects heart
health is through its impact on blood
lipids. A high level of low density
lipoproteins (LDL) indicates a high risk
of CHD. A high level of high density
lipoproteins (HDL) indicates a low risk
of CHD. Regular exercise—especially
when combined with a diet low in
saturated fat and cholesterol—reduces
LDL and increases HDL. These changes
in blood lipid levels lower the risks of
coronary heart disease.
Exercise improves heart health
by lowering blood pressure. Exercise
15-10 Responding to their opponents’
movements requires goalies to have good
reaction time.